kite

9 Articles

Radio Frequency Burns, Flying A Kite, And You

April 21, 2024 by 22 Comments

Most hams can tell you that it’s possible to get a nasty RF burn if you accidentally touch an antenna while it’s transmitting. However, you can also cop a nasty surprise on the receiving end if you’re not careful, as explained in a video from [Grants Pass TV Repair].

It’s hard to see in a still image, but the RF burns from the kite antenna actually generate a little puff of smoke on contact.

An experiment was used to demonstrate this fact involving a kite and a local AM broadcaster. A simple calculation revealed that an antenna 368 feet and 6 inches long would be resonant with the KAJO Radio signal at 1.270 MHz. At half the signal’s wavelength, an antenna that long would capture plenty of energy from the nearby broadcast antenna.

Enter the kite, which served as a skyhook to loft an antenna that long. With the wire in the air picking up a strong signal from the AM radio tower, it was possible to get a noticable RF burn simply by touching the end of the antenna.

The video explains that this is a risky experiment, but not only because of the risk of RF burn itself. It’s also easy to accidentally get a kite tangled in power lines, or to see it struck by lightning, both of which would create far greater injuries than the mild RF burn seen in the video. In any case, even if you know what you’re doing, you have to be careful when you’re going out of your way to do something dangerous in the first place.

AM radio towers aren’t to be messed with; they’ve got big power flowing. Video after the break.

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Kites Fill Electricity Generation Gaps

January 22, 2024 by 47 Comments

Looking at a wind turbine from first principles, it’s essentially a set of wings that generate lift in much the same way an airplane wing does. Putting the wings on a rotor and calling them “blades” is not a huge step away from that. But there’s no reason the wing has to rotate, or for that matter be attached to a fixed platform, in order to generate electricity. Anything that generates lift can be used, and this company is demonstrating that with their kite-powered wind generators.

Like other wind energy producers that have used kites to generate electricity, this one is similar in that the kite is flown in a figure-8 pattern downwind where it can harness energy the most efficiently, pulling out a tether which is tied to a generator. When fully extended, it is flown to a position where the wind doesn’t strike the kite as strongly and the tether is reeled in. Unlike other kite generators we’ve seen, though, this one is offered as a turnkey system complete with battery backup and housed in a self-contained shipping unit, allowing it to be deployed quickly to be used in situations where something like a diesel generator would be impossible to get or where the fuel can’t be obtained.

The company, called Kitepower, does note that these aren’t replacements for traditional wind turbines and would be used more for supporting microgrids. There are still some advantages to using kites over fixed turbine blades though: kites can reach higher altitude where the wind is stronger, and they require less materials for a given amount of energy production, often making them even more environmentally friendly and possibly more economical as well. Surprisingly enough, kites can also be used to generate energy even in places where there’s no wind at all.

Go Fly A Kite

November 13, 2022 by 17 Comments

Harvesting energy from the wind has been a commercially viable way of generating clean energy for around three decades now. Wind turbines are a reliable, proven technology but they do have some downsides, one of which is that since there’s more wind higher above the ground this usually means tall, expensive towers. There is a way around this problem, though, which is using kites to generate energy instead of a fixed turbine.

While kite generators aren’t a new idea, [Benjamin] has been working on this kite generator which has a number of improvements over existing kite generators. Like other kite generators, this one uses a tether to spin a generator which is located on the ground. But while this is similar to other kite systems, this prototype has a much simpler design and sweeps a much larger area while in flight. It also has an autopilot with multiple independent steering systems, which [Benjamin] says will allow it to stay in flight for months at a time provided there is enough wind. If there isn’t, it can land reliably, and launching it is relatively fast and simple as well.

While kites do have some obvious downsides compared to fixed turbines including a single point of failure at the tether and a large amount of cleared area to operate, they have plenty of advantages as well. They’re smaller, simpler, require no complicated yaw system, and can be easily maintained on the ground. In fact, it’s possible to build very simple kite generators out of nothing more than a hobby kite and some readily-available electrical components.

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Automatic Rewinder Makes Kite Retrieval A Breeze

August 21, 2019 by 25 Comments

So you’ve built a fine kite, taken it to the beach, and let it ride the wind aloft on a spool of line. Eventually it has to come down, and the process of reeling all that line that was so easily paid out is likely a bigger chore than you care to face. What to do?

If you’re like [Matt Bilsky], the answer is simple: build a motorized kite reel to bring it back in painlessly. Of course what’s simple in conception is often difficult to execute, and as the second video below shows, [Matt] went through an extensive design and prototype phase before starting to create parts. Basic questions had to be answered, such as how much torque would be needed to reel in the kite, and what were the dimensions of a standard kite string reel. With that information and a cardboard prototype in hand, the guts of a cordless drill joined a bunch of 3D-printed parts to form the running gear. We really liked the research that went into the self-reversing screw used to evenly wind the string across the spool; who knew that someone could do a doctoral dissertation on yarn-winding? Check out the “Reeler-Inner” in action in the first, much shorter video below.

With some extra power left from the original drill battery, [Matt] feature-crept a bit with the USB charger port and voltmeter, but who can blame him? Personally, we’d have included a counter to keep track of how much line is fed out; something like this printer filament counter might work, as long as you can keep the sand out of it.

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Gaming System Built With Kite, The DIY Android Kit

May 29, 2018 by 8 Comments

As a gamer, [Lexie Dostal] dreamed of a smartphone that was a viable gaming platform: something with enough power to run the games and emulators he was interested in, with the controls to make playing them feel natural. So when he got his hands on an early version of Kite, the modular open hardware platform designed to be hacked and customized, that’s exactly what he decided to build. The Kite kit would provide the touch screen and Android-equipped motherboard, he just needed to design a case and integrate controls to make it a real gaming device.

The case design [Lexie] came up with is inspired by the bottom half of the Nintendo 3DS, and ended up only a few centimeters wider than the stock case from the Kite kit. Unfortunately, his delta 3D printer wasn’t large enough to fit the device’s case, so he ended up having to break it into five separate pieces and glue them together. With the case in one piece he worked his way from 220 to 400 grit sand paper, filling any voids in the print with glue as he went. A few coats of primer, more sanding, and a final matte texture spray give the final case a very professional-looking finish.

Not only was the Nintendo 3DS an inspiration for the device, it was also a donor for some of the parts. The directional pad, analog “nub”, and buttons are replacement 3DS hardware, which is interfaced to the KiteBoard with an Arduino Nano. When he couldn’t find springs small enough to use for the shoulder buttons, he bought some thin music wire and wound them himself. Talk about attention to detail.

There’s quite a bit of gear packed into the case, but [Lexie] thinks there’s probably still room to make some improvements. He could free up some room by dropping the connectors and soldering everything directly, and says he’d like to come up with a custom PCB to better interface with the 3DS’s hardware to cut down on some of the wiring required. With the extra room he thinks the battery, currently a 3200 mAh pack designed for the LG V20 smartphone, could probably be replaced with something even bigger.

Readers may recall that the Kite is currently in the running for the 2018 Hackaday prize. Seeing Kite already delivering on the promise of making it easier to develop powerful Android devices is very exciting, and we can’t wait to see what else hackers will be able to do with it.

Daisy Kite Wind Turbine: Now You Can Buy One

November 25, 2016 by 25 Comments

The Isle of Lewis is the largest of the Scottish Outer Hebrides, sitting in the North Atlantic off the west coast of the Scottish mainland. It is the first landfall after thousands of miles of ocean for a continuous stream of Atlantic weather systems, so as you might imagine it is a place in which there is no shortage of wind.

It is thus the perfect situation for a wind power startup, and in the aptly-named Windswept and Interesting Ltd it has one that is pushing the boundaries. Their speciality is the generation of power from spinning kites, arrays of kites that transmit power to a ground-based generator through the rotation of their lines, and because they release their designs as open source they are of extra interest to us.

Of course, if you are a seasoned reader you’ll now be complaining that we’ve covered this story before when they had an entry in the 2014 Hackaday Prize, so what’s new? The answer is that the 2014 story was a much earlier iteration than their current multi-level kite array, and that they have now reached the point of bringing their products to market. You can buy one of their prototypes right now, and there is a soon-to-be-launched crowdfunding campaign for their latest model. It’s not exactly cheap, but this first product is the result of 5 years of product development, and it is pretty obvious that more is on the way. For any open hardware startup to stay afloat that long is an impressive achievement, to do so in a field in which you are not surrounded by a huge supporting industry in the way for example electronics startups are is nothing short of amazing.

If you would like to have a go at building one of their spinning kites, you can do so with full instructions released under a Creative Commons licence, but for non kite builders their website is a fascinating read in its own right. Their YouTube channel  in particular has a wealth of videos of previous tests as well as design iterations, and is one on which many readers will linger for a while. Below the break we’ve put one of their most recent, a montage showing the kite evolution over the years.

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Build A Circular Aerofoil Kite

July 5, 2016 by 13 Comments

[Waalcko] fell in love with kites when he was 13 years old. He saw a NASA Para Wing kite fly and couldn’t get it out of his head. Now, years later, he shares how to build a circular foil kite design he came up with.

We’re all particular about our chosen hobbies. Some of us like one design direction and hate another. For [Waalcko], he really hates internal supports in kites. When he spied a single line kite in a circular foil configuration he was enraptured, but the design had those hideous spars. So, he got to work and pushed himself to the limit coming up with a kite that was a circular foil, flew with one line, and had no internal supports.

His instructable is a great read and goes into deep detail about the basics of kite construction. (After reading it we’re certain that even the shallows have depths when it comes kites.) It goes through the terminology used when talking about kits, the techniques used to assemble them, the common problems, and more.

Many hours later, if all goes well, one should end up with a really cool kite.